To effectively implement the cache of PHP applications, first enable OPcache to improve script execution efficiency; secondly, output cache for static pages; secondly, use Memcached or Redis to cache data; finally control browser cache through HTTP headers. 1. Enable OPcache and configure the memory and file count parameters. 2. Generate cache files for frequent access to the page and determine whether they need to be regenerated when requesting. 3. Store database results, API responses, etc. in Redis or Memcached, and set the key name policy and expiration time. 4. Set up HTTP headers such as Cache-Control and ETag to optimize the caching effect of APIs and static resources, reduce bandwidth usage and speed up loading.
Caching is one of the most effective ways to improve performance in a PHP application. It helps reduce database load, speeds up page loads, and improves user experience. If you're looking to implement caching in your PHP app, here's how to do it effectively.
1. Use Opcode Caching with OPcache
One of the simplest and most impactful caching methods is opcode caching. PHP scripts are compiled into opcode every time they're executed — unless you cache it.
Enable OPcache:
- Make sure
opcache.so(orphp_opcache.dllon Windows) is enabled in yourphp.ini. - Set
opcache.enable=1 - For production, enable
opcache.enable_cli=1if you run CLI scripts. - Adjust
opcache.memory_consumptionandopcache.max_accelerated_filesbased on your app size.
This doesn't require any changes to your code and give an immediate performance boost.
2. Cache Output or Full Pages for Frequently Accessed Content
If your site has pages that don't change often — like a homepage or a product listing — caching the full HTML output can save a lot of processing time.
How to do it:
- Create a cache file for each page (eg, using a unique key like the URL).
- Before generating the page, check if a cached version exists and is still fresh.
- If so, serve it directly without executing the full PHP logic.
- Otherwise, generate the page and save it to the cache.
$cacheFile = 'cache/' . md5($_SERVER['REQUEST_URI']);
if (file_exists($cacheFile) && (time() - 3600 < filemtime($cacheFile))) {
readfile($cacheFile);
exit();
}
// Generate page content normally
ob_start();
echo '<html>...your content...</html>';
file_put_contents($cacheFile, ob_get_contents());
ob_end_flush();This approach works best for static or semi-static pages.
3. Use Data Caching for Repeated Queries or Expensive Operations
Sometimes, you just need to cache specific data instead of whole pages. This is especially useful for:
- Database query results
- API responses
- Heavy computings
You can store these in fast storage systems like Memcached or Redis .
Basic example with Redis:
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$key = 'user_profile_123';
$data = $redis->get($key);
if (!$data) {
// Simulate expensive fetch
$data = json_encode(['name' => 'John Doe', 'visits' => 100]);
$redis->setex($key, 300, $data); // Cache for 5 minutes
}
echo $data;Make sure to:
- Choose a good key naming strategy.
- Set appropriate expiration times.
- Clear or update the cache when underlying data changes.
4. Leverage HTTP Caching for APIs and Static Assets
If your PHP app serves APIs or static assets (like images, CSS, JS), use HTTP headers to control browser caching.
Common headers to set:
-
Cache-Control: Tells browsers how long to cache the response. -
ETag/Last-Modified: Help browsers validate whether their cached copy is still valid.
For example:
header('Cache-Control: public, max-age=86400'); // Cache for 24 hours header('Last-Modified: ' . gmdate('D, d MYH:i:s', filemtime('style.css')) . ' GMT');
This reduces bandwidth usage and makes repeat visits faster.
Implementing caching in PHP doesn't have to be complicated. Start with OPcache, then add page or data caching where it makes sense. Don't forget to manage cache invalidation properly — otherwise, you might end up serving outdated content.
Basically that's it.
The above is the detailed content of How Can You Implement Caching in a PHP Application?. For more information, please follow other related articles on the PHP Chinese website!
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